Crystalline and amorphous pyrimidine compounds and processes for preparing pyrimidine compounds

ABSTRACT

Crystals of 5-[2-amino-4-(2-furyl)pyrimidin-5-yl]-1-methylpyridin-2(1H)-one having a diffraction peak at a diffraction angle (2θ±0.2°) of 9.7° and/or 21.9° in a powder X-ray diffraction are suitable for an active ingredient of a preventing and therapeutic agent for diseases such as constipation. Crystals of 5-[2-amino-4-(2-furyl)pyrimidin-5-yl]-1-methylpyridin-2(1H)-one hydrate and amorphous 5-[2-amino-4-(2-furyl)pyrimidin-5-yl]-1-methylpyridin-2(1H)-one hydrate are also suitable for an active ingredient of a preventing and therapeutic agent for diseases such as constipation.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to a provisional application Ser. No.60/663,580 filed on Mar. 21, 2005 by the same Applicant, which is herebyincorporated by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to crystalline and amorphous pyrimidinecompounds, and processes for preparing the same. More particularly, thepresent invention relates to crystals (the crystal form C) of5-[2-amino-4-(2-furyl)pyrimidin-5-yl]-1-methylpyridin-2(1H)-one, acompound effective for prevention and treatment for various diseasessuch as constipation, and processes for preparing the same; crystals of5-[2-amino-4-(2-furyl)pyrimidin-5-yl]-1-methylpyridin-2(1H)-one hydrateand processes for preparing the same; and amorphous5-[2-amino-4-(2-furyl)pyrimidin-5-yl]-1-methylpyridin-2(1H)-one andprocesses for preparing the same. The present invention relates also toprocesses for preparing pyrimidine compounds such as5-[2-amino-4-(2-furyl)pyrimidin-5-yl]-1-methylpyridin-2(1H)-one andintermediates thereof.

2. Related Background of the Invention

5-[2-Amino-4-(2-furyl)pyrimidin-5-yl]-1-methylpyridin-2(1H)-one is acompound having adenosine receptor antagonism and being effective forprevention and treatment for various diseases such as constipation (seepatent document 1). Patent document 1, Example 16 discloses5-[2-amino-4-(2-furyl)pyrimidin-5-yl]-1-methylpyridin-2(1H)-one wasobtained as crystals.

The process for preparing5-[2-amino-4-(2-furyl)pyrimidin-5-yl]-1-methylpyridin-2(1H)-onedisclosed in patent document 1 is, as shown in the reaction schemebelow, a method of allowing2-(6-chloro-3-pyridyl)-3-dimethylamino-1-(2-furyl)-2-propene-1-one toreact with guanidine to afford5-(6-chloro-3-pyridyl)-4-(2-furyl)-2-pyrimidinylamine, oxidizing this toafford 5-[2-amino-4-(2-furyl)-5-pyrimidinyl]-1,2-dihydro-2-pyridinone,and then methylating this.

Also is disclosed in patent document 1, a method of acidizing5-(6-benzyloxy-3-pyridyl)-4-(2-furyl)-2-pyrimidinylamine to afford5-[2-amino-4-(2-furyl)-5-pyrimidinyl]-1,2-dihydro-2-pyridinone.

Furthermore, the following reaction is described as general productionmethod D in patent document 1.

In the above formula, R^(1d) represents a C6-14 aromatic hydrocarbonring group, a 5- to 14-membered aromatic heterocyclic group, etc., butthe reaction in which R^(1d) is N-alkyl pyridone is not specificallydisclosed.

Patent Document 1: WO 03/035639

SUMMARY OF THE INVENTION

The active ingredient of a drug must be stably supplied as a product ofconsistent quality. Therefore, when the active ingredient of a drug isobtained as a crystalline substance, it preferably consists of ahomogenous crystal form with suitable physical properties such as goodsolubility. Therefore an object of the present invention is to providecrystals of5-[2-amino-4-(2-furyl)pyrimidin-5-yl]-1-methylpyridin-2(1H)-one havingsuitable physical properties.

According to the process for preparing pyrimidine compounds such as5-[2-amino-4-(2-furyl)pyrimidin-5-yl]-1-methylpyridin-2(1H)-onedisclosed in patent document 1, the two steps are necessary in order toobtain N-alkyl pyridone, the final product, from a pyridine form: (1)oxidation from pyridine to pyridone; and (2) N-alkylation of pyridonering. In general, preparing process having fewer steps is industriallyadvantageous. Furthermore, an alkyl halide and a base are necessary forN-alkylation of pyridone ring. Alkyl halides are easily degradable inthe presence of a base, consequently are required more than oneequivalent with respect to starting materials, but it is requested thatthe amount of alkyl halides used should be reduced due to theirtoxicity. Therefore, another object of the present invention is toprovide a process for preparing pyrimidine compounds such as5-[2-amino-4-(2-furyl)pyrimidin-5-yl]-l-methylpyridin-2(1H)-one havingan advantage of fewer steps and less amount of alkyl halides used.

As a result of much avid research, the present inventors have discoveredcrystalline and amorphous5-[2-amino-4-(2-furyl)pyrimidin-5-yl]-1-methylpyridin-2(1H)-one whichare superior in solubility than the crystals disclosed in patentdocument 1 (hereinafter referred to as the crystal form B), and havesucceeded in completing this invention.

Specifically, the present invention provides the following [1] to [9].

-   [1] A crystal of    5-[2-amino-4-(2-furyl)pyrimidin-5-yl]-1-methylpyridin-2(1H)-one    having a diffraction peak at a diffraction angle (2θ±0.2°) of 9.7°    and/or 21.9° in a powder X-ray diffraction.-   [2] A crystal of    5-[2-amino-4-(2-furyl)pyrimidin-5-yl]-1-methylpyridin-2(1H)-one    having a peak at a chemical shift of approximately 134.9 ppm and/or    approximately 146.3 ppm in a ¹³C solid state nuclear magnetic    resonance spectrum (hereinafter referred to as ¹³C solid state NMR    spectrum).-   [3] A process for preparing a crystal according to [1] or [2], by    heating and drying amorphous    5-[2-amino-4-(2-furyl)pyrimidin-5-yl]-1-methylpyridin-2(1H)-one at a    high-temperature region.-   [4] A crystal of    5-[2-amino-4-(2-furyl)pyrimidin-5-yl]-1-methylpyridin-2(1H)-one    hydrate.-   [5] A crystal of    5-[2-amino-4-(2-furyl)pyrimidin-5-yl]-1-methylpyridin-2(1H)-one    monohydrate.-   [6] A crystal of    5-[2-amino-4-(2-furyl)pyrimidin-5-yl]-1-methylpyridin-2(1H)-one    hydrate having a diffraction peak at a diffraction angle (2θ±0.2°)    of 8.8° in a powder X-ray diffraction.-   [7] A process for preparing a crystal according to any one of [4] to    [6], by humidifying a crystal according to [1] or [2].-   [8] Amorphous    5-[2-amino-4-(2-furyl)pyrimidin-5-yl]-1-methylpyridin-2(1H)-one    hydrate.-   [9] A process for preparing an amorphous compound according to [8],    by lyophilizing a solution of    5-[2-amino-4-(2-furyl)pyrimidin-5-yl]-1-methylpyridin-2(1H)-one.

The present inventors have discovered a process for preparing pyrimidinecompounds such as5-[2-amino-4-(2-furyl)pyrimidin-5-yl]-1-methylpyridin-2(1H)-one, havingfewer steps and less amount of alkyl halides used than that disclosed inpatent document 1, and have succeeded in completing this invention.

Specifically, the present invention provides the following [10] to [22].

-   [10] A process for preparing a compound (I), a salt or a hydrate of    the foregoing

wherein R¹ represents C1-6 alkyl and R² and R³ independently representhydrogen or C1-6 alkyl, by allowing a compound (II)

wherein R¹ is as defined above, to react with a compound (III)

wherein R² and R³ are as defined above.

-   [11] A process according to [10], wherein a compound (IV)

wherein R1 represent C1-6 alkyl, is allowed to react withN,N-dimethylformamide dimethyl acetal to afford the compound (II).

-   [12] A process according to [10], wherein a compound (V)

wherein R¹ represent C1-6 alkyl, is allowed to react with a compound(VI)RXwherein R represents C1-6 alkyl and X represents halogen, to afford acompound (IV)

wherein R¹ is as defined above, and the compound (IV) is allowed toreact with N,N-dimethylformamide dimethyl acetal to afford the compound(II).

-   [13] A process according to [10], wherein a compound (VII)

wherein R¹ represent C1-6 alkyl and Y represent a leaving group, isallowed to react with a compound (VIII)

wherein Q represents morpholino or trimethylsilyl, to afford a compound(V)

wherein R¹ is as defined above, and the compound (V) is allowed to reactwith a compound (VI)RXwherein R represents C1-6 alkyl and X represents halogen, to afford acompound (IV)

wherein R¹ is as defined above, and the compound (IV) is allowed toreact with N,N-dimethylformamide dimethyl acetal to afford the compound(II).

-   [14] A process according to any one of [10] to [13], wherein R¹ is    methyl.-   [15] A process according to any one of [10] to [14], wherein R² and    R³ are hydrogen.-   [16] A process according to [13], wherein Y is halogen.-   [17] A process according to [13], wherein Y is chlorine.-   [18] A process according to [13], wherein Q is morpholino.-   [19] A process according to any one of [12] to [18], wherein the    compound (VI) is added at a catalytic amount with respect to the    compound (V).-   [20]    5-[2-Dimethylamino-1-(furan-2-carbonyl)-vinyl]-1-methyl-1H-pyridin-2-one.-   [21] 5-(2-Furan-2-yl-2-oxo-ethyl)-1-methyl-1H-pyridin-2-one.-   [22] 1-Furan-2-yl-2-(6-methoxy-pyridin-3-yl)-ethanone.

The crystal form C of5-[2-amino-4-(2-furyl)pyrimidin-5-yl]-1-methylpyridin-2(1H)-one(hereinafter referred to as simply “the crystal form C”), the crystalsof 5-[2-amino-4-(2-furyl)pyrimidin-5-yl]-1-methylpyridin-2(1H)-onehydrate (hereinafter referred to as simply “the hydrate crystals”) andthe amorphous5-[2-amino-4-(2-furyl)pyrimidin-5-yl]-1-methylpyridin-2(1H)-one(hereinafter referred to as simply “the amorphous compound”) accordingto the present invention have suitable physical properties such as goodsolubility and are suitable for using as an active ingredient of apreventing and therapeutic agent for diseases such as constipation.

Furthermore, the processes for preparing5-[2-amino-4-(2-furyl)pyrimidin-5-yl]-1-methylpyridin-2(1H)-oneaccording to the present invention have advantage of fewer steps andless amount of alkyl halides used and are industrially advantageous.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a drawing representing a powder X-ray diffraction pattern ofthe crystals obtained in Comparative Example 1.

FIG. 2 is a drawing representing a powder X-ray diffraction pattern ofthe crystals obtained in Comparative Example 2.

FIG. 3 is a drawing representing a powder X-ray diffraction pattern ofthe crystals obtained in Comparative Example 3.

FIG. 4 is a drawing representing a powder X-ray diffraction pattern ofthe crystals obtained in Example 4A.

FIG. 5 is a drawing representing a powder X-ray diffraction pattern ofthe crystals obtained in Example 5.

FIG. 6 is a drawing representing a powder X-ray diffraction pattern ofthe crystals obtained in Example 6.

FIG. 7 is a drawing representing temperature-dependent changes of powderX-ray diffraction patterns of the crystals obtained in ComparativeExample 1.

FIG. 8 is a drawing representing temperature-dependent changes of powderX-ray diffraction patterns of the crystals obtained in ComparativeExample 3.

FIG. 9 is a drawing representing temperature-dependent changes of powderX-ray diffraction patterns of the crystals obtained in Example 4A.

FIG. 10 is a drawing representing DSC patterns of the crystals obtainedin Comparative Example 1, Comparative Example 3 and Example 4A.

FIG. 11 is a magnification of the DSC patterns in FIG. 10 in a range of40-230° C.

FIG. 12 is a drawing representing a DSC pattern of the amorphouscompound obtained in Example 6.

FIG. 13 is a drawing representing a ¹³C solid state NMR spectrum of thecrystals obtained in Comparative Example 3.

FIG. 14 is a drawing representing a ¹³C solid state NMR spectrum of thecrystals obtained in Example 4A.

FIG. 15 is a drawing representing an infrared absorption spectrum of thecrystals obtained in Comparative Example 3.

FIG. 16 is a drawing representing an infrared absorption spectrum of thecrystals obtained in Example 4A.

FIG. 17 is a graph showing the results in Test Example 1.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Crystal Form C

The crystals (the crystal form C) of5-[2-amino-4-(2-furyl)pyrimidin-5-yl]-1-methylpyridin-2(1H)-oneaccording to the invention are characterized by having a diffractionpeak at a diffraction angle (2θ±0.2°) of 9.7° and/or 21.9° in a powderX-ray diffraction and characterized by having a peak at a chemical shiftof approximately 134.9 ppm and/or approximately 146.3 ppm in a ¹³Csolid-state NMR spectrum. These characteristic peaks in a powder X-raydiffraction and a ¹³C solid-state NMR spectrum are not observed for thecrystals disclosed in patent document 1, example 16 (the crystal formB). Typical powder X-ray diffraction pattern and ¹³C solid-state NMRspectrum for the crystal form C are shown in FIG. 4 and FIG. 9,respectively. A typical infrared absorption spectrum for the crystalform C is shown in FIG. 16. The crystal form C is superior in solubilitythan the crystal form B.

Since the diffraction angle (2θ) in a powder X-ray diffraction generallyhas a diffraction angle error in the range of ±0.2°, the aforementionedvalues for the diffraction angle must be interpreted as including valueswithin a range of ±0.2°. Thus, the present invention encompasses notonly crystals whose peak diffraction angle in a powder X-ray diffractionmatches exactly, but also crystals whose peak diffraction angle matcheswith an error of ±0.2°.

Specifically, throughout the present specification, “having adiffraction peak at a diffraction angle (2θ±0.2°) of 9.7°” means “havinga diffraction peak at a diffraction angle (2θ) in the range of9.5°-9.9°”, “having a diffraction peak at a diffraction angle (2θ±0.2°)of 21.9°” means “having a diffraction peak at a diffraction angle (2θ)in the range of 21.7°-22.1°”. “Having a diffraction peak at adiffraction angle (2θ±0.2°) of 9.7° and/or 21.9°” means having at leastone of the above diffraction peaks.

Throughout the present specification, “having a peak at a chemical shiftof approximately 134.9 ppm” means “having a peak substantiallyequivalent to a chemical shift of 134.9 ppm, when a ¹³C solid state NMRspectrum is measured under ordinary measuring conditions”, and “having apeak at a chemical shift of approximately 146.3 ppm” means “having apeak substantially equivalent to a chemical shift of 146.3 ppm, when a¹³C solid state NMR spectrum is measured under ordinary measuringconditions”. “Having a peak at a chemical shift of approximately 134.9ppm and/or approximately 146.3 ppm” means having at least one of theabove peaks.

Process for Preparing the Crystal Form C

The process for preparing the crystal form C of the invention ischaracterized by heating and drying amorphous5-[2-amino-4-(2-furyl)pyrimidin-5-yl]-1-methylpyridin-2(1H)-one at ahigh-temperature region. The amorphous5-[2-amino-4-(2-furyl)pyrimidin-5-yl]-1-methylpyridin-2(1H)-one isobtainable by the preparing process described below.

Drying at a high-temperature region means standing at a temperature of40 to 80° C. for 12 to 24 hours, preferably standing at 60° C. for 20hours.

Hydrate Crystals

The crystals of5-[2-amino-4-(2-furyl)pyrimidin-5-yl]-1-methylpyridin-2(1H)-one hydrateaccording to the invention are preferably crystals of monohydrate, andare preferably characterized by having a diffraction peak at adiffraction angle (2θ±0.2°) of 8.8° in a powder X-ray diffraction. Atypical powder X-ray diffraction pattern of the hydrate crystals isshown in FIG. 5. The hydrate crystals are superior in solubility thanthe crystal form B.

Throughout the present specification, “having a diffraction peak at adiffraction angle (2θ±0.2°) of 8.8°” means “having a diffraction peak ata diffraction angle (2θ) in the range of 8.6°-9.0°”

Process for Preparing the Hydrate Crystals

The process for preparing the hydrate crystals of the invention ischaracterized by humidifying a crystal form C of5-[2-amino-4-(2-furyl)pyrimidin-5-yl]-1-methylpyridin-2(1H)-one.

Conditions for the humidification means standing in an atmospherekeeping a relative humidity of 90 to 100%, at 1 to 30° C. for 12 to 36hours, and preferably standing in an atmosphere of a relative humidityof 95%, at 1 to 30° C. for 24 hours. Humidification is preferablycarried out under a nitrogen stream.

Amorphous Compound

The amorphous5-[2-amino-4-(2-furyl)pyrimidin-5-yl]-1-methylpyridin-2(1H)-one issuperior in solubility than the crystal form B.

Process for Preparing the Amorphous Compound

The process for preparing the amorphous compound according to theinvention is characterized by lyophilizing a solution of5-[2-amino-4-(2-furyl)pyrimidin-5-yl]-1-methylpyridin-2(1H)-one.5-[2-Amino-4-(2-furyl)pyrimidin-5-yl]-1-methylpyridin-2(1H)-one used maybe in any form. That is, it may be a hydrate or anhydrate, amorphous orcrystalline (including combinations of multiple crystal forms) compound,or a mixture thereof.5-[2-Amino-4-(2-furyl)pyrimidin-5-yl]-1-methylpyridin-2(1H)-one can beprepared by the method disclosed in patent document 1, and also by themethod described in Preparation Examples 1 to 6 below.

The solvent used for dissolution of5-[2-amino-4-(2-furyl)pyrimidin-5-yl]-1-methylpyridin-2(1H)-one is notrestricted so long as it dissolves the starting material to some extent,and is for example a single solvent or a mixed solvent of two or moreselected from a group consisting of an alcoholic solvent such asmethanol, ethanol, 2-propanol and n-propanol, an amide solvent such asacetonitrile and N,N-dimethylformamide, an ester solvent such as ethylacetate and water. Preferred solvent is a mixed solvent of an alcoholicsolvent such as methanol, ethanol and t-butyl alcohol and water, morepreferable solvent is a mixed solvent of t-butyl alcohol and water, andthe most preferable solvent is a mixed solvent of t-butyl alcohol andwater with a mixing ratio of 1:1.

The lyophilization can be carried out under conditions usually known tothose skilled in the art. For example, after the solution is frozen, thetemperature is gradually or stepwise raised from around −80° C. up toaround room temperature in a freeze-dryer.

Pharmaceutical Composition Comprising the Crystal Form C, the HydrateCrystals or the Amorphous Compound

The use of5-[2-amino-4-(2-furyl)pyrimidin-5-yl]-1-methylpyridin-2(1H)-one as atherapeutic agent for constipation is disclosed in detail in patentdocument 1, and the crystal form C, the hydrate crystals and theamorphous compound may be used in a similar fashion as the activeingredient of a therapeutic agent for constipation. The entirety of thedisclosure of patent document 1 is incorporated by reference into thedisclosure of the present specification. Moreover, the crystal form C,the hydrate crystals and the amorphous compound has satisfactorystability and physical properties and are hence the most suitable formfor use of5-[2-amino-4-(2-furyl)pyrimidin-5-yl]-1-methylpyridin-2(1H)-one as theactive ingredient of a therapeutic agent for constipation.

The crystal form C, the hydrate crystals or the amorphous compound maybe formulated by an ordinary method into tablets, powder, fine powder,granules, coated tablets, capsules, syrup, lozenges, an inhalant,suppository, injection, ointment, eye ointment, eye drop, nose drop, eardrop, pap, lotion or the like. For formulation there may be employedcommonly used excipients, binders, lubricants, coloring agents, tastecorrectives and, if necessary, stabilizers, emulsifiers, absorptionaccelerators, surfactants, pH adjustors, antiseptics, antioxidants andthe like, while other components ordinarily used as starting materialsfor drug formulation may also be added according to common procedures.

As examples of such components there may be mentioned animal orvegetable oils such as soybean oil, beef tallow and syntheticglycerides; hydrocarbons such as liquid paraffin, squalene and solidparaffin; ester oils such as octyldodecyl myristate and isopropylmyristate; higher alcohols such as cetostearyl alcohol and behenylalcohol; silicone resins; silicone oils; surfactants such aspolyoxyethylene fatty acid ester, sorbitan fatty acid ester, glycerinfatty acid ester, polyoxyethylenesorbitan fatty acid ester,polyoxyethylene hydrogenated castor oil andpolyoxyethylene-polyoxypropylene block copolymer; water-soluble polymerssuch as hydroxyethylcellulose, polyacrylic acid, carboxyvinyl polymer,polyethylene glycol, polyvinylpyrrolidone and methylcellulose; loweralcohols such as ethanol and isopropyl alcohol; polyhydric alcohols suchas glycerin, propylene glycol, dipropylene glycol and sorbitol; sugarssuch as glucose and sucrose; inorganic powders such as silicicanhydride, magnesium aluminum silicate and aluminum silicate, purifiedwater, and the like.

As examples of excipients there may be mentioned lactose, corn starch,white soft sugar, glucose, mannitol, sorbit, crystalline cellulose,silicon dioxide and the like, as examples of binders there may bementioned polyvinyl alcohol, polyvinyl ether, methylcellulose,ethylcellulose, gum Arabic, tragacanth gum, gelatin, shellac,hydroxypropylmethylcellulose, hydroxypropylcellulose,polyvinylpyrrolidone, polypropylene glycol-polyoxyethylene blockpolymer, meglumine and the like, as examples of disintegrators there maybe mentioned starch, agar, gelatin powder, crystalline cellulose,calcium carbonate, sodium hydrogencarbonate, calcium citrate, dextrin,pectin, carboxymethylcellulose calcium and the like, as examples oflubricants there may be mentioned magnesium stearate, talc, polyethyleneglycol, silica, hydrogenated vegetable oils and the like, as examples ofcoloring agents there may be mentioned those approved for addition topharmaceuticals, and as examples of taste correctives there may bementioned cocoa powder, menthol, aromatic powder, peppermint oil,camphor, cinnamon powder and the like.

For production of an oral preparation, the crystal form C, the hydratecrystals or the amorphous compound may be combined with an excipientand, if necessary, a binder, disintegrator, lubricant, coloring agent,taste corrective or the like and then made into a powder, fine powder,granules, tablets, coated tablets or capsules.

Also, there is no restriction against sugar-coating and, if necessary,other appropriate coating of the tablets or granules.

For production of a liquid preparation such as a syrup or pharmaceuticalpreparation for injection, the crystal form C, hydrate crystals oramorphous compound may be combined with a pH adjustor, solubilizer,isotonizing agent or the like, and if necessary, with a dissolving aid,stabilizers or the like, and formulated by an ordinary method.

The method of producing an external preparation is not particularlyrestricted, and may be according to an ordinary method. Specifically, asbase materials for pharmaceutical preparation there may be used variousmaterials ordinarily employed for pharmaceuticals, quasi drugs,cosmetics and the like. As examples of specific base materials to beused there may be mentioned materials such as animal and vegetable oils,mineral oils, ester oils, waxes, higher alcohols, fatty acids, siliconeoils, surfactants, phospholipids, alcohols, polyhydric alcohols,water-soluble polymers, clay minerals, purified water and the like, andif necessary there may also be added pH adjustors, antioxidants,chelating agents, antiseptic/mildew resistant agents, coloring agents,aromatics and the like, although base materials for an externalpreparation of the invention are not limited to these. If necessarythere may also be included components such as circulation promoters,bactericidal agents, antiflash agents, cell activators, vitamins, aminoacids, humectants, keratolytic agents and the like. The amounts of suchbase materials are the amounts which give concentrations indicated forproduction of ordinary external preparations.

The form of administration of the crystal form C, the hydrate crystalsor the amorphous compound is not particularly restricted, and may beoral administration or parenteral administration by an ordinarilyemployed method. For example, the crystals may be administered afterformulation into tablets, powder, granules, capsules, syrup, lozenges,an inhalant, suppository, injection, ointment, eye ointment, eye drop,nose drop, ear drop, pap, lotion or the like. The dosage of apharmaceutical according to the invention may be appropriately selecteddepending on patient age, gender, body weight, severity of symptoms,particular type of condition, and on the type of dosage form or salt.For example, it will generally be administered once or divided overseveral times at about 30 μg to 10 g, preferably 100 μg to 5 g, morepreferably 100 μg to 100 mg per day for adults in the case of oraladministration or 30 μg to 1 g, preferably 100 μg to 500 mg, morepreferably 100 μg to 30 mg per day in the case of injection administeredonce or divided over several times a day.

Process for Preparing the Compound (I)

The process for preparing the compound (I)

wherein R¹ represents C1-6 alkyl and R² and R³ independently representhydrogen or C1-6 alkyl, according to the present invention ischaracterized by allowing a compound (II)

wherein R¹ is as defined above, to react with a compound (III)

wherein R² and R³ are as defined above. This preparing process has anadvantage of fewer steps than the conventional preparing process (thepreparing process describe in patent document 1).

As examples of the “C1-6 alkyl”, there may be mentioned straight-chainor branched-chain groups such as methyl, ethyl, n-propyl, isopropyl,n-butyl, isobutyl, s-butyl, t-butyl, n-pentyl, isopentyl, s-pentyl,t-pentyl, 2-methylbutyl, 1-methylbutyl, 2-methylbutyl, neopentyl,1,1-dimethylpropyl, 1,2-dimethylpropyl, 1-ethylpropyl, n-hexyl,isohexyl, 4-methylpentyl, 3-methylpentyl, 2-methylpentyl,1-methylpentyl, 3,3-dimethylbutyl, 2,2-dimethylbutyl, 1,1-dimethylbutyl,1,2-dimethylbutyl, 1,3-dimethylbutyl, 2,3-dimethylbutyl, 1-ethylbutyl,2-ethylbutyl, 1,1,2-trimethylpropyl, 1,2,2-trimethylpropyl,1-ethyl-1-methylpropyl or 1-ethyl-2-methylpropyl, among which C1-4groups are preferred, methyl, ethyl or t-butyl is more preferred.

R¹ is preferably methyl, and R² and R³ are preferably hydrogen.

The solvent used for the reaction of the compound (II) and the compound(III) is not restricted so long as it dissolves the starting materialsto some extent and does not inhibit the reaction, for example, there maybe mentioned N,N-dimethylformamide, 1-metyl-2-pyrrolidone,N,N′-dimetylindanone and acetonitrile. The compound (III) may be used1.0 to 3.0 equivalents with respect to the compound (II). The reactionmay be carried out in the presence of a base such as1,8-diazabicyclo[5.4.0]undec-7-ene. The base may be used 1.5 to 3.0equivalents with respect to the compound (II). The reaction time may be1.5 to 48 hours. The reaction temperature may be 25 to 80° C.

The compound (II) is preferably obtained by allowing a compound (IV)

wherein R1 represent C1-6 alkyl, to react with N,N-dimethylformamidedimethyl acetal. The solvent used for the reaction of the compound (IV)and N,N-dimethylformamide dimethyl acetal is not restricted so long asit dissolves the starting materials to some extent and does not inhibitthe reaction, for example, there may be mentioned N,N-dimethylformamide,1-metyl-2-pyrrolidone, N,N′-dimetylindanone and acetonitrile.N,N-Dimethylformamide dimethyl acetal may be used 1.5 to 3.0 equivalentswith respect to the compound (IV). The reaction time may be 2 to 22hours. The reaction temperature may be 60 to 80° C. To a reactionmixture in which the compound (IV) is allowed to react withN,N-dimethylformamide dimethyl acetal to produce the compound (II) maybe added the compound (III), without isolating the compound (II), toafford the compound (I).

The compound (IV) is preferably obtained by allowing a compound (V)

wherein R¹ represent C1-6 alkyl, to react with a compound (VI)RXwherein R represents C1-6 alkyl and X represents halogen.

Halogen is fluorine, chlorine, bromine or iodine. R is preferablymethyl, and X is preferably iodine.

The solvent used for the reaction of the compound (V) and the compound(VI) is not restricted so long as it dissolves the starting materials tosome extent and does not inhibit the reaction, for example, there may bementioned N,N-dimethylformamide, 1-metyl-2-pyrrolidone,N,N′-dimetylindanone, dimethylsulfoxide and t-butyl alcohol. Thecompound (VI) is preferably used at a catalytic amount with respect tothe compound (V), and more preferably used 0.3 to 1.0 equivalents. Thereaction time may be 3 to 7 hours. The reaction temperature may be 80 to100° C.

The compound (V) is preferably obtained by allowing a compound (VII)

wherein R¹ represent C1-6 alkyl and Y represent a leaving group, toreact with a compound (VIII)

wherein Q represents morpholino or trimethylsilyl.

Y means a leaving group such as halogen, mesyloxy or trifluoromethyloxy,and is preferably halogen and more preferably chlorine. Q is preferablymorpholino.

The solvent used for the reaction of the compound (VII) and the compound(VIII) is not restricted so long as it dissolves the starting materialsto some extent and does not inhibit the reaction, for example, there maybe mentioned tetrahydrofuran, 1,2-dimethoxyethane, t-butyl methyl etherand toluene. The compound (VIII) may be used 1.05 to 1.15 equivalentswith respect to the compound (VII). The reaction time may be 1 to 3hours. The reaction temperature may be −20 to 0° C.

Where the compound (I) is5-[2-amino-4-(2-furyl)pyrimidin-5-yl]-1-methylpyridin-2(1H)-one, thefollowing compounds are useful as intermediates:5-[2-dimethylamino-1-(furan-2-carbonyl)-vinyl]-1-methyl-1H-pyridin-2-one,5-(2-furan-2-yl-2-oxo-ethyl)-1-methyl-1H-pyridin-2-one and1-furan-2-yl-2-(6-methoxy-pyridin-3-yl)-ethanone.

EXAMPLES Preparation Example 1 Synthesis of(6-methoxypyridin-3-yl)methanol (2)

To a solution of methyl-6-methoxynicotinate (1) (650 g, 3.89 mol) int-butyl methyl ether (hereinafter abbreviated as “MTBE”) (6.5 L) cooledin an ice bath was added sodium bis(2-methoxyethoxy)aluminum hydride(65% solution in toluene, 1.45 kg, 4.67 mol) under a nitrogen atmosphereover a period of 1.3 hours. After stirring for 20 minutes, a 3.5 Naqueous solution of sodium hydroxide (2.6 L) was added to the reactionmixture while keeping the temperature 15° C. or below. The reactionmixture was stirred at 32° C. for 45 minutes and then the organic layerwas separated and the aqueous layer was re-extracted with MTBE (2.3 L).The organic layers were combined and concentrated under reduced pressureto dryness, and then toluene (1.3 L) was added to the residue andazeotropic distillation was carried out. Azeotropic distillation withtoluene (1.3 L) was repeated three times to give 597 g of the titlecompound as a pale yellow oil (yield 100%).

¹H-NMR (CDCl₃) δ (ppm): 8.11 (1H, d, J=2.4 Hz), 7.62 (1H, dd, J=2.4 Hz,8.8 Hz), 6.75 (1H, d, J=8.8 Hz), 4.62 (2H, s), 3.93 (3H, s)

Preparation Example 2 Synthesis of 5-chloromethyl-2-methoxypyridine (3)

To a solution of (6-methoxypyridin-3-yl)methanol (2) (537.8 g, 3.86 mol)obtained in Preparation Example 1 in dimethylformamide (1.6 L) was addeddropwise thionyl chloride (310 mL, 4.25 mol) over a period of 1.3 hourswhile cooling in an ice bath under a nitrogen atmosphere. After stirringfor 1 hour while cooling in an ice bath, toluene (5.4 L) and a 2Naqueous solution of sodium hydroxide (5.4 L) were added successively tothe reaction mixture at 23° C. or below. The reaction mixture wasstirred for about 10 minutes and then the aqueous layer was separated,the organic layer was washed with water (2.7 L). The organic layer wasconcentrated under reduced pressure to dryness, and then toluene (1.0 L)was added to the residue and azeotropic distillation was carried out togive 618.8 g of the title compound as a pale yellow oil (content 556.3g, yield 91.4%).

¹H-NMR (CDCl₃) δ (ppm): 8.15 (1H, d, J=2.4 Hz), 7.63 (1H, dd, J=2.4 Hz,8.4 Hz), 6.75 (1H, d, J=8.4 Hz), 4.55 (2H, s), 3.94 (3H, s)

Preparation Example 3 Synthesis offuran-2-yl-morpholin-4-yl-acetonitrile (5)

A solution of furfural (4) (550 g, 5.72 mol) in toluene (5.5 L) wascooled to 8° C, and then an aqueous solution (1.1 L water) of potassiumcyanide (384.6 g, 5.72 mol) was added over a period of 7 minutes.

Then, to the reaction mixture was added an aqueous solution (1.65 Lwater) of p-toluenesulfonic acid monohydrate (1143.0 g, 6.01 mol) over aperiod of 20 minutes, and the reaction mixture was further stirred for 1hour. To the reaction mixture was added a solution of morpholine (997 g,11.45 mol) in toluene (100 mL) over a period of 8 minutes, followed bystirring for 2.5 hours in a water bath at 20° C. The aqueous layer wasseparated, and the organic layer was washed with water (2.75 L) and thenconcentrated under reduced pressure to dryness to give 1028.7 g of thetitle compound as a reddish-brown oil (content 90.2%, yield 84.3%).

¹H-NMR (CDCl₃) δ (ppm): 7.47 (1H, brs), 6.57 (1H, d, J=3.2 Hz), 6.41(1H, dd, J=3.2 Hz, 1.6 Hz), 4.85 (1H, s), 4.43 (4H, m), 4.31 (4H, m)

Example 1 Synthesis of 1-furan-2-yl-2-(6-methoxy-pyridin-3-yl)-ethanone(7)

A solution of furan-2-yl-morpholin-4-yl-acetonitrile (5) (818.0 g,content 737.9 g, 3.84 mol) obtained in Preparation Example 3 and5-chloromethyl-2-methoxypyridine (3) (611.8 g, content 550.0 g, 3.49mol) obtained in Preparation Example 2 in toluene (4.4 L) was cooled to−15° C, and then a solution of potassium-t-butoxide (508.9 g, 4.54 mol)in tetrahydrofuran (4.4 L) was added at −5° C. or below over a period of72 minutes, and the reaction mixture was further stirred for 1.5 hours.

Next, to the reaction mixture was added a 6N aqueous solution ofhydrochloric acid (4.4 L), followed by heating to 70° C. and stirringfor 2 hours. The reaction mixture was cooled to 5° C. and a 3N aqueoussolution of sodium hydroxide (3.0 L) was added at 20° C. or below. Theorganic layer was separated, the aqueous layer was re-extracted withtoluene (6.0 L), and the organic layers were combined and concentratedunder reduced pressure to dryness to give 828.5 g of the title compoundas a brown oil (content 647.8 g, yield 85.5%).

2-Furan-2-yl-3-(6-methoxy-pyridin-3-yl)-2-morpholin-4-yl-propionate (6)

¹H-NMR (CDCl₃) δ (ppm): 7.71 (1H, d, J=2.4 Hz), 7.48 (1H, d, J=1.6 Hz),7.11 (1H, dd, J=2.4 Hz, 8.4 Hz), 6.56 (1H, d, J=8.4 Hz), 6.27 (2H, m),3.87 (3H, s), 3.80 (4H, m), 3.38 (1H, d, J=13.2), 3.26 (1H, d, J=13.2),2.78-2.81 (2H, m), 2.45-2.78 (2H, m)

1-Furan-2-yl-2-(6-methoxy-pyridin-3-yl)-ethanone (7)

¹H-NMR (CDCl₃) δ (ppm): 8.08 (1H, d, J=2.4 Hz), 7.61 (1H, d, J=1.7 Hz),7.53 (1H, dd, J=2.4 Hz, 8.2 Hz), 7.24 (1H, d, J=3.6 Hz), 6.71 (1H, d,J=8.2 Hz), 6.55 (1H, dd, J=1.7 Hz, 3.6 Hz), 4.05 (2H, s), 3.91 (3H, s)

Example 2 Synthesis of5-(2-furan-2-yl-2-oxo-ethyl)-1-methyl-1H-pyridin-2-one (8)

To a solution of 1-furan-2-yl-2-(6-methoxy-pyridin-3-yl)-ethanone (7)(800.0 g, content 625.6 g, 2.88 mol) obtained in Example 1 inN-methyl-2-pyrrolidine (NMP) (1.88 L) was added iodomethane (122.6 g,0.86 mol), and the reaction mixture was stirred at 100° C. for 3 hoursand then at room temperature for 17.5 hours. To the reaction mixture wasadded dropwise MTBE (6.6 L) over a period of 77 minutes, followed bystirring for 1 hour while cooling in an ice bath. The precipitatedcrystals were collected by filtration and washed with MTBE (2.0 L), andthen dried under reduced pressure at 50° C. for 3 hours to give 692.0 gof a crude product of the title compound as a dark brown powder (content536.4 g, yield 85.7%).

To the obtained crude product (682.0 g, content 528.7 g, 2.43 mol) wereadded 1,2-dimethoxyethane (hereinafter abbreviated as “DME”) (7.93 L)and water (0.68 L), followed by heating and stirring at 80° C. for 75minutes. After confirming dissolution, stirring was continued overnightat 8° C. The precipitated crystals were collected by filtration andwashed with DME (2.0 L), and then air-dried at 60° C. for 2.3 hours togive 468.46 g of the title compound as pale yellow crystals (content462.8 g, yield 87.5%).

¹H-NMR (DMSO) δ (ppm): 8.02 (1H, d, J=1.6 Hz), 7.57 (2H, m), 7.30 (1H,dd, J=3.4 Hz, 9.2 Hz), 6.74 (1H, dd, J=1.6 Hz, 3.6 Hz), 6.33 (1H, d,J=9.2 Hz), 3.98 (2H, s), 3.38 (3H, s)

Example 3A Synthesis of5-[2-amino-4-(2-furyl)pyrimidin-5-yl]-1-methylpyridin-2(1H)-one (10)

To 5-(2-furan-2-yl-2-oxo-ethyl)-1-methyl-1H-pyridin-2-one (8) (402.0 g,content 397.6 g, 1.83 mol) obtained in Example 2 were addeddimethylformamide (0.4 L) and N,N-dimethylformamide dimethyl acetal(654.4 g, 5.49 mol), and the reaction mixture was stirred at 60° C. for10.5 hours and then at room temperature for 13.5 hours. To the reactionmixture were added guanidine hydrochloride (524.56 g, 5.49 mol) and1,8-diazabicyclo[5.4.0]undec-7-en (DBU) (821 mL, 5.49 mol), and thereaction mixture was stirred for 7.8 hours at 70° C. Next, to thereaction mixture was added 2-propanol (12.0 L), followed by stirring for2 hours in an ice bath. The precipitated crystals were collected byfiltration, washed with 2-propanol (1.0 L), and then air-dried at 60° C.for 13 hours to give 424.9 g of the title compound as pale yellowcrystals (content 413.0 g, yield 84.1%).

5-[2-Dimethylamino-1-(furan-2-carbonyl)-vinyl]-1-methyl-1H-pyridin-2-one(9)

¹H-NMR (CDCl₃) δ (ppm): 7.77 (1H, s), 7.45 (1H, d, J=2.0 Hz), 7.26 (1H,dd, J=2.4 Hz, 9.2 Hz), 7.14 (1H, dd, J=2.4 Hz), 6.60 (1H, d, J=9.2 Hz),6.50 (1H, J=3.2 Hz), 6.37 (1H, J=3.2 Hz), 3.55 (3H, s), 2.93 (6H, brs)

5-[2-Amino-4-(2-furyl)pyrimidin-5-yl]-1-methylpyridin-2(1H)-one (10)

¹H-NMR (DMSO) δ (ppm): 8.13 (1H, s), 7.75 (1H, dd, J=0.7 Hz, 1.4 Hz),7.72 (1H, d, J=2.4 Hz), 7.20 (1H, dd, J=2.4 Hz, 9.0 Hz), 6.78 (2H, brs),6.72 (1H, d, J=3.5 Hz), 6.56 (1H, m), 6.36 (1H, d, J=9.0 Hz), 3.44 (3H,s)

Preparation Example 3B Synthesis of5-[2-amino-4-(2-furyl)pyrimidin-5-yl]-1-methylpyridin-2(1H)-one (10)

To 5-(2-furan-2-yl-2-oxo-ethyl)-1-methyl-1H-pyridin-2-one (8) (10.0 g,46.04 mmol) obtained in Example 2 were added dimethylformamide (20 mL),N,N-dimethylformamide dimethyl acetal (9.21 mL, 69.06 mmol) and DBU(10.3 mL, 69.06 mmol), and the reaction mixture was stirred at 80° C.for about 5 hours and then allowed to cool. Next, to the reactionmixture was added 2-propanol (100 mL), and the reaction mixture wasstirred at 8° C. for about 16 hours. The precipitated crystals werecollected by filtration, washed with 2-propanol (45 mL), and thenair-dried at 50° C. for 20 minutes to give 10.2 g of a crude product ofthe title compound (10) as pale yellow crystals (content 10.2 g, yield82.3%).

Comparative Example 1 Preparation of Crystal Form A(1)

To 30 g of crude5-[2-amino-4-(2-furyl)pyrimidin-5-yl]-1-methylpyridin-2(1H)-one (10)obtained in Example 3A were added 30 mL of 2-propanol and 150 mL ofwater, followed by heating and stirring for 25 minutes in an oil bath at90° C. Upon confirming the absence of solid, filtration with heating wasperformed and the filtrate was heated and stirred at 70° C. for about 30minutes. It was then heated and stirred for 1.3 hours at an externaltemperature of 55° C, and subsequently stirred for 2.3 hours at anexternal temperature of 45 to 40° C. Precipitation of crystals wasconfirmed at an internal temperature of approximately 47° C. Thereaction mixture was further stirred at 30° C. for about 40 minutes, atroom temperature for 1 hour and at 4° C. for 1.6 hours, and then thecrystals were collected by filtration. The crystals were washed 3 timeswith 20 mL of 2-propanol and dried at 60° C. for 10.5 hours to give 19.9g of the crystal form A.

Comparative Example 2 Preparation of the Crystal Form B(1)

To a suspension of5-[2-amino-4-(2-furyl)pyrimidinyl]-1,2-dihydro-2-pyridinone (2.2 g, 8.65mmol) in methanol (44 mL) was added sodium methoxide (940 mg, 17.4 mmol)at room temperature under a nitrogen atmosphere, followed by stirring.After 15 minutes, iodomethane was added (1.6 mL, 25.7 mmol), followed bystirring for 22 hours. The reaction mixture was concentrated, and waterwas added to the residue, and the precipitates were collected byfiltration and washed with water to give crude crystals of the titlecompound (1.98 g). This was suspended in ethanol, and the precipitateswere collected by filtration and washed with ethanol to give5-[2-amino-4-(2-furyl)pyrimidin-5-yl]-1-methylpyridin-2(1H)-one (1.54 g,66%) as a pale yellow solid (the crystal form B).

Comparative Example 3 Preparation of the Crystal Form B(2)

To 10 g of crude5-[2-amino-4-(2-furyl)pyrimidin-5-yl]-1-methylpyridin-2(1H)-one (10)were added 10 mL of 2-propanol and 50 mL of water, followed by heatingand stirring for about 30 minutes at an external temperature of 85° C.Upon confirming dissolution, the solution was cooled in an ice bath andstirred for 1.5 hours, and the crystals were collected by filtration.The crystals were washed twice with 10 mL of 2-propanol and dried at 60°C. for 10.5 hours to give 6.84 g of the crystal form B.

Example 4A Preparation of the Crystal Form C(1)

After thoroughly dissolving 5.43 g of crude5-[2-amino-4-(2-furyl)pyrimidin-5-yl]-1-methylpyridin-2(1H)-one (10) in1 L of t-butyl alcohol/water (1:1, v/v), the mixture was filtered usinga suction filter and a filter paper, and the filtrate was transferred toa stainless steel container and frozen in a freeze-dryer (Edwards Co.,Ltd.; S08 middle size freeze-dryer). Pressure reduction was initiatedafter cooling to a shelf temperature of −40° C. After elapse of 20 hoursat a pressure of 0.01 mbar, the shelf temperature was raised over aperiod of 25 hours until the shelf temperature reached 8° C. Thepressure was then increased to atmospheric pressure, and the obtainedsolid was taken from the freeze-dryer and allowed to stand at 60° C. for19 hours. It was subsequently allowed to stand at room temperature for43 hours under a nitrogen stream to give a white solid.

Example 4B Preparation of the Crystal Form C(2)

The crystals obtained in Comparative Example 1 (the crystal form A)(5.43 g) were dissolved in 1 L of t-butyl alcohol/water (1:1, v/v) andfiltered. Then, the obtained filtrate was placed in a freeze-dryer andlyophilized. The conditions of time and temperature of lyophilization isas follows.

TABLE 1 lyophilization time (hour) setting temperature (° C.) 46 −80 1610 9 20

Taken from the freeze-dryer, the amorphous compound is obtained. Then,the obtained amorphous compound (whole amount) was allowed to stand inan oven at a temperature of 60° C. for 20 hours to give crystal form C.

Example 5 Preparation of the Hydrate Crystals

By constantly flowing a nitrogen gas with a relative humidity of 95%into a desiccator, the relative humidity in the desiccator was keptapproximately 95%. The crystal form C obtained in Example 4B (330 mg)was placed therein and allowed to stand at room temperature for about 24hours to give the hydrate crystals.

Example 6 Preparation of the Amorphous Compound

The crystal form A obtained in Comparative Example 1 (1.21 g) wasdissolved in 200 mL of t-butyl alcohol/water (1:1, v/v) and filtered.Then, the obtained filtrate was placed in a freeze-dryer andlyophilized. The conditions of time and temperature of lyophilization isas follows.

TABLE 2 lyophilization time (hour) setting temperature (° C.) 15 −80 24−20 3 0 24 10

Taken from the freeze-dryer, the amorphous compound is obtained.

Measurement of Powder X-ray Diffraction Pattern

The X-ray diffraction patterns of the respective crystals obtained inComparative Example 1A, Comparative Example 2, Comparative Example 3,Example 4A, Example 5 and Example 6 (the crystal form A, the crystalform B(1), the crystal form B(2), the crystal form C, the hydratecrystals and the amorphous compound) were measured under the followingconditions. The powder X-ray diffraction patterns of the respectivecrystals are shown in FIG. 1 to 6. Table 3 shows the characteristicdiffraction (2θ) peaks for the respective crystals.

-   Target/tube current/tube voltage: Cu/40 kV/200 mA-   Monochrometer: Curved crystal monochrometer-   Counter: Scintillation counter-   Scan speed: 2°/min-   Scan step: 0.02°-   Scanning axis: 2θ/θ-   Scanning range: 5-40°-   Divergence slit: 0.5°-   Scattering slit: 0.5°-   Receiving slit: 0.3 mm

TABLE 3 Crystal 2θ (°) Crystal form A 12.8 18.1 23.5 Crystal form B 7.016.4 Crystal form C 9.7 21.9 Hydrate crystals 8.8

Measurement of Variable-Temperature Powder X-ray Diffraction Pattern

Changes in the powder X-ray diffraction pattern, with increase in thesample temperature from 30° C. to 260° C., were observed for therespective crystals obtained in Comparative Example 1, ComparativeExample 3 and Example 4A (the crystal form A, the crystal form B(2) andthe crystal form C). The measuring conditions were the same as for thepowder X-ray diffraction pattern measurement described above, except forthe measuring temperature. The temperature-dependent changes in thepowder X-ray diffraction pattern of the respective crystals are shown inFIG. 7 to 9.

Thermal Analysis (Differential Scanning Calorimetry; DSC)

DSC analysis was conducted under the following conditions, usingapproximately 3 mg each of the crystals obtained in Comparative Example1, Comparative Example 3 and Example 4A (the crystal form A, the crystalform B(2) and the crystal form C). The DSC patterns of the respectivecrystals are shown in FIG. 10 and FIG. 11 (magnification of 40-230° C.).DSC analysis was conducted under the same conditions, usingapproximately 4 mg of the amorphous compound obtained in Example 6. TheDSC pattern of the amorphous compound is shown in FIG. 12. Theendothermic peaks and exothermic peaks are shown in Table 4.

-   Measuring apparatus: DSC822^(e) by Mettler Toledo-   Sample pan material: aluminum-   Nitrogen gas flow (40 mL/min)-   Start temperature: 25° C.-   End temperature: 260° C.-   Temperature elevating rate: 5° C./min

TABLE 4 Crystal Peak form, onset temperature Crystal form A Endothermicpeak, about 248° C. Crystal form B Endothermic peak, about 92° C.Exothermic peak, about 165° C. Endothermic peak, about 248° C. Crystalform B Exothermic peak, about 154° C. Endothermic peak, about 248° C.Hydrate crystals Exothermic peak, about 57° C. Endothermic peak, about249° C.

For the crystal form A, no change in the powder X-ray diffractionpattern was seen from 30° C. to 250° C., but disappearance ofcrystallinity was observed at 260° C. The endothermic peak around 248°C. found by DSC analysis of the crystal form A was shown to haveappeared due to melting of the crystals. These results indicated thatthe crystal form A undergoes no change in crystal form by heating in arange from ordinary temperature to its melting point of about 248° C.

For the crystal form B, a significant change in the powder X-raydiffraction pattern was observed between 90 and 100° C. A significantchange in the powder X-ray diffraction pattern was also observed between160 and 180° C., with disappearance of crystallinity being observed at260° C. The endothermic peak around 92° C. and the exothermic peakaround 165° C. found by DSC analysis were shown to have appeared due tothese changes in the crystal form. The powder X-ray diffraction patternalso indicated a change to the same crystal form as the crystal form Aat 180° C. and higher. These results indicated that the crystal form Btransforms to another crystal form (B′) at about 90° C., after which ittransforms to the crystal form A at about 170° C. and melts at about248° C. as the crystal form A.

For the crystal form C, a significant change in the powder X-raydiffraction pattern was observed between 160 and 190° C. The exothermicpeak around 154° C. found by DSC analysis of the crystal form C wasshown to have appeared due to change in the crystal form. The powderX-ray diffraction pattern also indicated a change to the same crystal asthe crystal form A at 190° C. and higher. These results indicated thatthe crystal form C transforms to the crystal form A at about 170° C. andmelts at about 248° C. as the crystal form A.

Measurement of ¹³C Solid State NMR Spectrum

¹³C solid state NMR spectra for the respective crystals obtained inComparative Example 3 and Example 4 (the crystal form B(2) and thecrystal form C) were measured under the following conditions. The ¹³Csolid state NMR spectra for the respective crystals are shown in FIG. 13and FIG. 14. Table 5 shows chemical shifts for the respective crystals.Characteristic peaks in 110.6 ppm and 117.2 ppm were found for thecrystal form B, whereas characteristic peaks in 134.9 ppm and 146.3 ppmwere found for the crystal form C.

-   Measuring apparatus: AVANCE 400 MHz (Bruker)-   Probe: 7 mm-CP/MAS (Bruker)-   NMR cell diameter: 7 mm-   Frequency of cell: 6000 round/sec-   Measurement method: CPTOSS method-   Latency: 10 sec-   Contact time: 5000 microseconds-   Accumulation: 1024 times-   External standard: setting the chemical shift of carbonyl carbon of    glycine as 176.03 ppm

TABLE 5 Crystal form B Crystal form C 162.5 162.4 159.4 158.5 153.1152.6 149.0 151.7 144.0 146.3 139.3 143.1 117.2 134.9 116.0 119.4 114.4115.9 110.6 114.7 37.4 113.2 111.5 36.4 Unit: ppm

Measurement of Infrared Absorption Spectrum

Infrared absorption spectra for the respective crystals obtained inComparative Example 3 and Example 4A (the crystal form B(2) and thecrystal form C) were measured under the following conditions. Theinfrared absorption spectra for the respective crystals are shown inFIG. 15 and FIG. 16. Table 6 shows wavenumber (cm⁻¹) of absorption peaksfor the respective crystals.

-   Measuring apparatus: FT/IR-620 (Jasco)-   Measurement method: ATR method-   Measuring range: 4000 cm⁻¹ to 650 cm⁻¹-   Resolution: 4 cm⁻¹

TABLE 6 Crystal form B Crystal form C 3410 1156 3464 1077 3300 1022 31461016 3102 1004 1671 884 1658 950 1644 857 1638 875 1603 802 1598 8381568 744 1529 803 1523 712 1495 781 1490 693 1474 750 1470 1436 709 14071397 1355 1359 1326 1329 1208 1217 1176 Unit: cm⁻¹

Test Example 1 Solubility

Approximately 50 mg each of the crystals and amorphous compound obtainedin Comparative Example 3, Example 4A, Example 5 and Example 6 (thecrystal form B(2), the crystal form C, the hydrate crystals and theamorphous compound) was used for evaluation of solubility inDisintegration Test, the 2nd fluid described in the Japanesepharmacopoeia, 14th Edition. First, 500 mL of the 2nd fluid was stirredat 50 rpm with paddles (Toyama Co., Ltd.; DISSOLUTION TESTER), thenafter the crystals and amorphous compound were added, the solution wassampled at each time period. The sampled solutions were filtered througha filter (0.2 μm), and the concentration of5-[2-amino-4-(2-furyl)pyrimidin-5-yl]-1-methylpyridin-2(1H)-one in thesolution was measured by HPLC method. The conditions for HPLC method areshown below. The obtained results were show in FIG. 17.

-   (HPLC conditions)-   Column: CAPCELL PAK C18 AQ, S-5 μm, 4.6 mm ID×250 mm length    (Shiseido, Japan)-   Column temperature: a constant temperature around 30° C.-   Detection wavelength: 262 nm-   Flow rate: 1.0 mL/min-   Mobile phase:-   Solution A: acetonitrile/water/1M ammonium acetate (10:1000:1,    v/v/v)-   Solution B: acetonitrile/water/1M ammonium acetate (900:100:1,    v/v/v)

TABLE 7 Gradient: Time (min) (B) conc. (%) 0 10 20 10 40 100 50 100 50.110 70 Stop

As shown in FIG. 17, it is clear that the crystal form C, the hydratecrystals and the amorphous compound are superior in solubility than thecrystal form B.

INDUSTRIAL APPLICABILITY

The present invention provides crystals of5-[2-amino-4-(2-furyl)pyrimidin-5-yl]-1-methylpyridin-2(1H)-one (crystalform C) which consist of a homogenous crystal form and are excellent insolubility and a process for preparing the same. The present inventionprovides also crystals of5-[2-amino-4-(2-furyl)pyrimidin-5-yl]-1-methylpyridin-2(1H)-one hydratewhich consist of a homogenous crystal form and are excellent insolubility and a process for preparing the same. The present inventionprovides also amorphous5-[2-amino-4-(2-furyl)pyrimidin-5-yl]-1-methylpyridin-2(1H)-one which isexcellent in solubility and a process for preparing the same. Thesecrystals and amorphous compound are suitable for using as an activeingredient of a pharmaceutical composition, particularly a therapeuticagent for constipation.

Furthermore, the present invention provides a process for preparing5-[2-amino-4-(2-furyl)pyrimidin-5-yl]-1-methylpyridin-2(1H)-one, whichhas less steps and amount of alkyl halides used. The preparing processis industrially advantageous.

1. A process for preparing a compound (I), a salt or a hydrate of theforegoing

wherein R¹ represents C1-6 alkyl and R² and R³ independently representhydrogen or C1-6 alkyl, by allowing a compound (II)

wherein R¹ is as defined above, to react with a compound (III)

wherein R² and R³ are as defined above.
 2. A process according to claim1, wherein R¹ is methyl.
 3. A process according to any one of claims 1or 2, wherein R² and R³ are hydrogen.